Personal flotation devices (PFD's), also known as life preservers, are designed to keep the wearer afloat at sea with the head sufficiently above water to enable breathing even in heavy seas. These are bulky and uncomfortable. They generally are made by sandwiching a very low density material such as closed cell foam, cork, or fiber such as kapok between waterproof layers of film or fabric.
In active play when a child perspires, these structures are so moisture impermeable that they do not permit the moisture to evaporate. They are so bulky and inflexible that they restrict a child's activity. Consequently, it is not surprising to find that children at play near dangerous waters do not wear a PFD.
Children at play near swimming pools, ponds and waterways cannot be supervised at all times, and cannot be expected to avoid the dangers. They may even overcome obstacles such as fences and doors intended to protect them.
Too many children drown as a result of this combination of circumstances. It would be desirable to provide children with a comfortable garment that they could wear at play that would keep them afloat if they should fall in the water.